have to用于现在完成时和现在进行时

问题描述

have to可用于一般现在时、一般将来时、一般过去时。如：

I have lost my pen, so I have to buy one. 我丢了钢笔，所以得去买一枝。

When you leave school you’ll have to find a job. 你毕业后，必须找个工作。

I had to show my pass to the man at the door.  我不得不向门口的那个人出示我的通行证。

但是，have to可用于现在完成时和现在进行时吗？

老师答疑

罗老师：

have to 用于现在完成时的例子并不少见。例如：
We have had to turn down four applicants already. 我们已经不得不回绝了四位申请人。
Not all companies have had to cut back on training. 不是所有公司都得削减培训费用。
Since his illness. He has had to swear off tennis. 他自从患病以来不得不停止打网球。
但是，进行时的不多见，网上也能查到一些例句，但是都没有权威性，还需要查查资料。

黎老师：